Activity Of Anaerobic Ammonium Oxidation Bacteria Research Articles

Effect of zero-valent iron (ZVI) on nitrogen and Fe(II) metabolism in anammox-hydroxyapatite (HAP) system under low-temperature stress

Low temperatures could inhibit the activity of anaerobic ammonium oxidizing bacteria (AnAOB). This study investigated the effect of exogenous zero-valent iron (ZVI) on Anammox-hydroxyapatite (HAP) system at 17 ± 1 °C. The results showed that long-term addition of ZVI increased the nitrogen removal efficiency by 8.59 %, and alleviated the inhibition of AnAOB under the condition of low temperature. After addition of ZVI, the activity of AnAOB and the heme c content increased by 58.20 % and 4.83 %, respectively. Moreover, the functional enzyme activities of NIR, HZS, and HZO increased by 94.12 %, 36.36 %, and 16.67 %, respectively. The concentrations of quorum sensing molecules, i.e., C6-HSL and C8-HSL, increased by 191.17 % and 41.54 %, respectively, after ZVI addition. Metagenomic analysis revealed that the addition of 5 g/L ZVI stimulated the relative abundance of Fe(II) metabolism-related genes in AnAOB at 17 ± 1 °C, thereby contributing to the uptake, transport, utilization, and storage of Fe(II). In summary, the addition of ZVI could improve the nitrogen removal performance of the anammox-HAP system at the low temperature.

Novel strategy for rapid start-up and stable operation of anammox: Negative pressure coupled with the direct-current electric field

An application challenge of anaerobic ammonia oxidation (anammox) is the slow proliferation rate of anaerobic ammonium oxidation bacteria (AnAOB). This study adopted negative pressure coupled with the direct-current electric field (NP–DCEF) to evaluate system nitrogen removal performance. Results showed that the total nitrogen removal rate (TNRR) of the NP–DCEF system was stable at 88.6% after seven days. Compared with that of the ordinary operating system (45.4%), the relative abundance of Candidatus–kuenenia considerably increased from 51.9% to 57.6%. Under transient and long-term influent fluctuation, the NP–DCEF system showed high nitrogen removal performance. The specific activity of AnAOB (SAA) reached 11.0 mg N∙g Vss−1 h−1 under load fluctuation, and it was 8.7 mg N∙g Vss−1 h−1 under ordinary operational conditions. In addition, the specific activities of hydrazine dehydrogenase (HDH) and hydrazine synthetase (HZS) reached 32.66 and 92.95 U∙L−1, which are considerably higher than those under the ordinary operating conditions (18.41 and 63.20 U∙L−1). These results indicated that the novel operation strategy has specific feasibility and potential for the start-up and long-term operation of anammox.

Promoting Nitrogen Removal in ANAMMOX Biofilm Reactor by Fe2+ Under Low Nitrogen Concentration

The feasibility for nitrogen removal in a two-stage ANAMMOX biofilm reactor promoted by Fe2+ under low nitrogen concentration was investigated. The results showed that the ANAMMOX reaction could be effectively promoted by a ρ(Fe2+) of 5, 10, and 15 mg·L-1. A ρ(Fe2+) of 10 mg·L-1 presented the highest promotion for the ANAMMOX reaction, with the highest nitrogen removal efficiency (NRE) of 81.71% under a ρ(TN) of 150 mg·L-1and a nitrogen loading rate (NLR) of 0.62 kg·(m3·d)-1. Fe2+ promoted the secretion of extracellular polymeric substance (EPS) and the synthesis of heme c in the ANAMMOX system. Batch test results further verified the positive effects by Fe2+on the activity of anaerobic ammonium oxidizing bacteria (AnAOB). The specific ANAMMOX activity (SAA) of 10 mg·L-1 ρ(Fe2+) was 3.6 times as high as that of the control group[ρ(Fe2+)=0 mg·L-1], whereas the activity of AnAOB was significantly inhibited with ρ(Fe2+) increased to 20 mg·L-1. High-throughput sequencing results showed that the addition of Fe2+ increased the abundance of Candidatus_Kuenenia. When ρ(Fe2+) was 10 mg·L-1, the relative abundance of Candidatus_Kuenenia in reactor 1 and reactor 2 increased to 16.18% and 4.22%, respectively. The stable operation of the two-stage ANAMMOX biofilm process promoted by Fe2+provides an alternative technology for low-strength nitrogen wastewater.

Influence of Tourmaline on the Activity of ANAMMOX Bacteria and ANAMMOX Reaction

AbstractThe performance of the anaerobic ammonium oxidation (ANAMMOX) process was investigated in two identical sequencing batch reactors (SBRs) [designated as SBR1 (tourmaline addition) and SBR2 (...

Inhibition kinetics and granular sludge in an ANAMMOX reactor treating mature landfill leachate.

The present study reports the inhibition kinetics and granular sludge in an anaerobic ammonium oxidation (ANAMMOX) - up-flow anaerobic sludge blanket reactor fed with diluted mature landfill leachate. The activity of ANAMMOX bacteria was inhibited by addition of mature landfill leachate, but gradually adapted to the leachate. The system achieved efficient nitrogen removal during 65-75 d and the average removal efficiencies for NH4+-N, NO2--N and total nitrogen (TN) were 96%, 95% and 87%, respectively. ANAMMOX was the main pathway of nitrogen removal in the system, and heterotrophic denitrification occurred simultaneously. In addition, aerobic ammonia oxidation and aerobic nitrite oxidation were active in this system. Inhibition kinetic experiments showed that the NH4+-N and NO2--N inhibition concentration threshold of ANAMMOX were 489.03 mg/L and 192.36 mg/L, respectively. ANAMMOX was significantly inhibited by mature landfill leachate, and was completely inhibited when the leachate concentration was 1,450.69 mg/L (calculated in chemical oxygen demand). Thus, the inhibition concentration of substrate and landfill leachate should be considered when applying the ANAMMOX process to landfill leachate. The color of granular sludge ANAMMOX changed from brick-red into a reddish-brown. The particle size increased from small to large, with evident granulation of the ANAMMOX sludge.

Long‐term addition of micro‐amounts of hydrazine enhances nitrogen removal and reduces NO and NO3− production in a SBR performing Anammox

AbstractBACKGROUNDN2H4 and NO are the important intermediates of Anammox. The appropriate addition of N2H4 weakens the inhibitory effect of NO2− on anaerobic ammonium oxidation bacteria (AnAOB) activity. The effect of long‐term addition of micro‐amounts of N2H4 was investigated in this study.RESULTSA sequencing batch reactor (SBR) performing Anammox could run stably during long‐term addition of micro‐amounts of N2H4. The nitrogen removal rate and efficiency of the SBR with micro‐amounts of N2H4 addition were higher than the SBR without N2H4 addition. The molar ratio of NO3− production to NH4+ removal (MRNN) decreased to 0.12, significantly lower than the expected stoichiometry of Anammox. The NO emission decreased by more than 15%. The addition of micro‐amounts of N2H4 could weaken the inhibition of NO2− to the activity of AnAOB.CONCLUSIONThe electrons released from the oxidation of added N2H4 by AnAOB acclimated under long‐term micro‐amounts of N2H4 addition replenish the loss of electrons due to the diffusive loss of intermediates in AnAOB metabolism, enhance the activity of AnAOB and accelerate the NO consumption with resulting decreased NO emission. The oxidation of added N2H4 partially substitutes the oxidation of NO2− to NO3− for the anabolism of AnAOB with resulting significantly decreased production of NO3−.© 2014 Society of Chemical Industry

Effect of low temperature on the performance of a gravity flow CANON-like pilot plant MBR treating surface water

A gravity flow completely autotrophic nitrogen removal over nitrite (CANON)-like pilot plant Membrane bio-reactor was designed to treat surface water for indirect potable reuse and was operated for over seven months with a constant Trans-membrane pressure of 100 mbar after the start-up phase. The effect of low temperature on the performance of autotrophic nitrogen removal over nitrite was investigated over a seven-month period during which the feed water temperature changed from 29°C to 1°C and the viscosity of the permeate more than doubled. The process showed good biostability and sustainability across the different seasons. Initially when the temperature fell below 10°C (which seems like a turning point for the activity of ANAMMOX bacteria) high fluctuations happened, but the activity of ANAMMOX bacteria recovered in 18 d. Increasing Hydrogen retention time during this period was the means by which one can successfully compensate for low temperature. The dissolved oxygen (DO) (7.12–10.9 mg/L) in the raw water supported the partial nitrification and anaerobic ammonium oxidation (ANAMMOX) process without the use of aeration. There was high ammonium (up to 5 mg/L) removal even at extremely low temperatures of 1°C.

Microbial activity of suspended biomass from a nitritation–anammox SBR in dependence of operational condition and size fraction

Single-stage nitritation-anammox combines the growth of aerobic ammonium-oxidizing bacteria (AOB) and anaerobic ammonium oxidizing bacteria (AnAOB) in one reactor. The necessary compromise of their milieu conditions often leads to the growth of nitrite-oxidizing bacteria (NOB). For this study, a sequencing batch reactor (SBR) for nitritation-anammox was operated for 180days with sewage sludge reject water (removal capacity, 0.4kg N m(-3) day(-1)). The growth of NOB was favored by enhanced oxygen supply rather than extended aerobic phases. Suspended-type biomass from this SBR was taken regularly and sieved into three size fractions (all of them <1,000μm). Batch experiments as well as fluorescence in situ hybridization were performed to study the distribution and activity of AnAOB, AOB, and NOB within those size fractions. Both the measured conversion rates and detected abundances decreased with increasing size fraction. The highest anammox conversion rates (15g NH4 (+)-N per kilogram VSS per hour) and the highest abundances of Brocadia fulgida were found in the medium size fraction (100-315μm). The batch experiments proved to be accurate tools for the monitoring of multiple processes in the reactor. The results were representative for reactor performance during the 6months of reactor operation.

Presence and activity of anaerobic ammonium-oxidizing bacteria at deep-sea hydrothermal vents

Recent studies indicate that ammonia is an important electron donor for the oxidation of fixed nitrogen, both in the marine water column and sediments. This process, known as anammox, has so far only been observed in a large range of temperature habitats. The present study investigated the role of anammox in hydrothermal settings. During three oceanographic expeditions to the Mid-Atlantic Ridge, hydrothermal samples were collected from five vent sites, at depths ranging from 750 to 3650 m from cold to hot habitats. Evidence for the occurrence of anammox in these particular habitats was demonstrated by concurrent surveys, including the amplification of 16S rRNA gene sequences related to known anammox bacteria, ladderanes lipids analysis and measurement of a (14)N(15)N dinitrogen production in isotope-pairing experiments at 60 and 85 degrees C. Together these results indicate that new deep-branching anammox bacteria may be active in these hot habitats.